1. Field of the Invention
The present invention relates generally to the field of material handling and more specifically to the handling of rolls of web material wound on cores in web production equipment.
2. Description of the Related Art
Many products, such as paper, tissue, textiles, plastics, films or polymer webs are wound on cylindrical cores in the machine producing the product. In this application, the word “web” will be used to refer to these materials and is intended to encompass all materials of a width greater than 10 inches (254 mm) that are wound onto any type of cylindrical cores, shafts or the like. Typically, the cores are cylindrical paper, cardboard, plastic, metal or composite tubes supported for rotation on shafts (also referred to as spools) in the production equipment. The shaft and its fully wound roll or rolls of web material must be periodically removed from the production equipment and replaced with another shaft equipped with empty cores. The removed shaft is then separated from the rolls of web material, provided with empty cores and re-used.
Past methods of separating the shaft from the rolls of web material have involved using a shaft-extracting device or a roll-extracting device. Shaft extracting devices hold the roll of web material in place by setting it on the floor, platform, or like surface, then attaching an external device to the shaft and pulling the shaft out of the roll cores. Shaft extractors may be fixed, or adjustable in elevation. Setting the fully wound, heavy rolls onto a surface will cause deformations and contamination. Deformation is illustrated in FIG. 1.
The roll-extracting devices separate one or more rolls from a shaft by fixing the shaft in a support device, usually cantilevered. Once the shaft is in the support, the elevation of the shaft (and hence the rolls) is changed to rest the tissue/web on a cart, or the like. Setting the rolls onto the cart surface as shown in FIG. 1 can contaminate and deform the web material. The cart is then moved in the opposite direction, away from the fixed support of the shaft, and pulls the rolls axially off the shaft.
Significant losses in product are caused by wholly or partially supporting fully wound rolls of web material on their outside surface as shown in FIG. 1. The wound web is flattened by the weight of the product combined with the weight of the shaft used to support the roll in the production equipment. Further damage can occur if the rolls of web material are transported on conveyors or with clamp trucks. The costs associated with these common practices include product losses due to damaged web material and the lower speed and increased web breaks in downstream production equipment due to flattened or misshapen rolls of web material.